possible grounding issue

[bernardgreen]

bonding and "earthing" are one and the same

You do NOT understand the difference. The only thing the same about earthing and bonding is the colour of the wire that is used.

In that quote you left out the bit about one of the bonded items being earthed. If none of the bonded items are earthed then that is bonding, to be precise it is earth free bonding.

If any one of the bonded items is earthed then all the bonded items are also earthed via the bond.

Please don't tell me that at 50 Hz the currents along any wires involved in bonding can be prevented from passing along a wire or pipe that takes earth to one or more of the bonded items.